A paper published by Ferguson online by Nature on 26 April examined strategies the US and the UK might use to contain a pandemic flu. Closing the borders and limiting domestic travel would not be effective. More successful strategies focus on isolating patients, quarantining their households, and using an antiviral drug prophylactically. A paper published by Cooper online in PLoS Medicine also concluded that travel bans would have little effect on the overall spread of the pandemic. The virus would reach cities around the globe only 2 days later if a travel ban were implemented after the first 100 cases. Only if an almost completely effective travel ban were implemented immediately after the first detection would a travel ban significantly slow the pandemic's global spread.